McMahon 1998.

Study characteristics
Methods	Study design: secondary analysis of RCT Country: USA Data collection period: not stated Registry ID: not reported
Participants	Number of participants: N = 844 Sample characteristics (at baseline): Age (Mean): 38 years; Sex (% male): 37% Population category: general population; Specific population: employees from worksites Nicotine dependence: not measured; Baseline cigarettes per day: 21; Motivation to quit: selected by motivation to quit
Interventions	Behavioural support for smoking cessation: a) self‐help manuals only which included strategies to learn about pattern (e.g. triggers, tracking habits), changing the pattern (e.g. making plan of action) and reinforcing quitting (e.g. anticipating smoking urges); b) self‐help manuals and incentives (USD 1 each day abstinent); or c) self‐help manuals, incentives and group support (cognitive behavioural techniques and social support) Pharmacological support for smoking cessation: no pharmacological support Psychotherapeutic or psychoactive support for mental health or mood: received mood management ‐ group intervention were taught relaxation techniques as aid for coping with stress and quitting
Outcomes	Definition of cessation used: point‐prevalence – self‐reported cessation (people who quit) Cessation definition used for outcome(s) in this analysis: point‐prevalence abstinence Measure of biovalidation: self‐reported abstinence verified using exhaled carbon monoxide (cut‐off point of 9 ppm); cotinine samples collected at end of 6‐month intervention Definition of people who continued to smoke used: not reported point‐prevalence abstinence at follow‐up Time point(s) at which follow‐up was conducted: pre‐test (prior to any intervention), post‐test (immediately following 3‐week intervention), 6‐months (immediately following 2nd phase of intervention) and 12, 18 and 24 months post‐test Outcome category: Stress Outcome measure(s): Perceived Stress Scale: Short Form (PSS‐4)
Funding source	None specified
Author conflicts of interest	None specified
Notes	Outcome data source: Published data Other: description of interventions and biovalidation measures detailed in the 1994 paper (McMahon, Jason & Salina, 1994)